The present invention relates to plasma processing methods such as dry etching, sputtering, and plasma CVD, as well as apparatuses therefor, to be used for manufacture of semiconductor or other electron devices and micromachines. More particularly, the present invention relates to a plasma processing method and apparatus for the use of plasma excited with high-frequency power of VHF or UHF band.
The present invention further relates to a matching box for a plasma processing apparatus to be used for impedance matching in supplying high-frequency power of VHF band, in particular, to a counter electrode for plasma excitation or to an antenna, and relates to a plasma processing method and apparatus using plasma excited with the high-frequency power of VHF band.
Japanese Laid-Open Patent Publication No. 8-83696 describes that the use of high-density plasma is important in order to meet the trend toward microstructures of semiconductors and other electron devices. Furthermore, low electron temperature plasma has recently been receiving attention by virtue of its high electron density and low electron temperature.
In the case where a gas having a high negativity, i.e., a gas that tends to generate negative ions, such as Cl2, SF6, is formed into plasma, when the electron temperature becomes about 3 eV or lower, larger amounts of negative ions are generated than with higher electron temperatures. Taking advantage of this phenomenon makes it possible to prevent etching configuration abnormalities, so-called notch, which may occur when positive charges are accumulated at the bottom of micro-patterns due to excessive incidence of positive ions. This allows etching of extremely micro patterns to be achieved with high precision.
Also, in the case where a gas containing carbon and fluorine, such as CxFy or CxHyFz (where x, y, z are natural numbers), which is generally used for etching of insulating films such as silicon oxide, is formed into plasma, when the electron temperature becomes about 3 eV or lower, gas dissociation is suppressed more than with higher electron temperatures, where, in particular, generation of F atoms, F radicals and the like is suppressed. Because F atoms, F radicals and the like are higher in the rate of silicon etching, insulating film etching can be carried out at larger selection ratios than silicon etching with lower electron temperatures.
Also, when the electron temperature becomes 3 eV or lower, ion temperature and plasma potential also becomes lower, so that ion damage to the substrate in plasma CVD can be reduced.
As a technique capable of generating plasma having low electron temperature, plasma sources using high-frequency power of VHF band or UHF band are now receiving attention.
FIG. 15 is a sectional view of a dual-frequency excitation parallel-flat plate type plasma processing apparatus. Referring to FIG. 15, while the interior of a vacuum chamber 201 is maintained at a specified pressure by introducing a specified gas from a gas supply unit 202 into the vacuum chamber 201 and simultaneously performing evacuation by a pump 203 as an evacuating device, a high-frequency power of 100 MHz is supplied to a counter electrode 205 by a counter-electrode-use-high-frequency power supply 204. Then, plasma is generated in the vacuum chamber 201, where plasma processing such as etching, deposition, and surface reforming can be carried out on a substrate 207 placed on a substrate electrode 206. In this case, as shown in FIG. 15, by supplying high-frequency power also to the substrate electrode 206 by a substrate-electrode-use-high-frequency power supply 208, ion energy that reaches the substrate 207 can be controlled. In addition, the counter electrode 205 is insulated from the vacuum chamber 201 by an insulating ring 211.
FIG. 16 is a sectional view of a plasma processing apparatus which we have already proposed and which has an antenna type plasma source mounted thereon. Referring to FIG. 16, while the interior of a vacuum chamber 301 is maintained at a specified pressure by introducing a specified gas from a gas supply unit 302 into the vacuum chamber 301 and simultaneously performing evacuation by a pump 303 as an evacuating device, a high-frequency power of 100 MHz is supplied to a spiral antenna 313 on a dielectric window 314 by an antenna-use-high-frequency power supply 312. Then, plasma is generated in the vacuum chamber 301 by electromagnetic waves radiated into the vacuum chamber 301, where plasma processing such as etching, deposition, and surface reforming can be carried out on a substrate 307 placed on a substrate electrode 306. In this case, as shown in FIG. 16, by supplying high-frequency power also to the substrate electrode 306 by a substrate-electrode-use-high-frequency power supply 308, ion energy that reaches the substrate 307 can be controlled.
However, there has been an issue that the conventional methods shown in FIGS. 15 and 16 have difficulty in obtaining uniform plasma generation.
FIG. 17 shows results of measuring ion saturation current density at a position just 20 mm above the substrate 207 in the plasma processing apparatus of FIG. 15. Conditions for plasma generation are gas type of Cl2 and gas flow rate of 100 sccm, a pressure of 1 Pa, and a high-frequency power of 2 kW. It can be understood from FIG. 17 that plasma density is higher in peripheral regions.
FIG. 18 shows results of measuring ion saturation current density at a position just 20 mm above the substrate 307 in the plasma processing apparatus of FIG. 16. Conditions for plasma generation are gas type of Cl2 and gas flow rate of 100 sccm, a pressure of 1 Pa, and a high-frequency power of 2 kW. It can be understood from FIG. 18 that plasma density is higher in peripheral regions.
Such nonuniformity of plasma is a phenomenon that could not be seen with the frequency of the high-frequency power of 50 MHz or less. Whereas the 50 MHz or higher high-frequency power needs to be used in order to lower the electron temperature of plasma, there are produced, in this frequency band, not only an advantage that plasma is generated by the counter electrode or antenna being capacitively or inductively coupled to the plasma, but also an advantage that plasma is generated by electromagnetic waves, which are radiated from the counter electrode or antenna, propagating on the surface of the plasma. In peripheral regions of the vacuum chamber, which serve as reflecting surfaces for the electromagnetic waves that have propagated on the surface of the plasma, stronger electric fields are developed so that thick plasma is generated.
Also, as described above, in the case where a gas having a high negativity, i.e., a gas that tends to generate negative ions, such as Cl2, SF6, is formed into plasma, when the electron temperature becomes about 3 eV or lower, larger amounts of negative ions are generated than with higher electron temperatures. Taking advantage of this phenomenon makes it possible to prevent a phenomenon that perpendicularity of the incident angle of ions onto the substrate worsens when positive charges are accumulated at the bottom of micro-patterns due to excessive incidence of positive ions. This allows etching of extremely micro patterns to be achieved with high precision. Besides, that is an expectation for process improvement making use of the high reactivity of negative ions.
Also, in the case where a gas containing carbon and fluorine, such as CxFy or CXHYFZ (where x, y, z are natural numbers), which is generally used for etching of insulating films such as silicon oxide, is formed into plasma, when the electron temperature becomes about 3 eV or lower, gas dissociation is suppressed more than with higher electron temperatures, where, in particular, generation of F atoms, F radicals and the like is suppressed. Because F atoms, F radicals and the like are higher in the rate of silicon etching, insulating film etching can be carried out at larger selection ratios than silicon etching with lower electron temperatures.
Also, when the electron temperature becomes 3 eV or lower, ion temperature and plasma potential also become lower, so that ion damage to the substrate in plasma CVD can be reduced.
It is plasma sources using high-frequency power of VHF band that is currently receiving attention as a technique capable of generating plasma low in electron temperature and capable of generating plasma superior in ignitability.
FIG. 24 is a sectional view of a dual-frequency excitation parallel-flat plate type plasma processing apparatus. Referring to FIG. 24, while the interior of a vacuum chamber 401 is maintained at a specified pressure by introducing a specified gas from a gas supply unit 402 into the vacuum chamber 401 and simultaneously performing evacuation by a pump 403 as an evacuating device, a high-frequency power of 100 MHz is supplied to a counter electrode 407 via a matching box 405 and a high-frequency coupling device (mount) 406 by a counter-electrode-use-high-frequency power supply 404. Then, plasma is generated in the vacuum chamber 401, where plasma processing such as etching, deposition, and surface reforming can be carried out on a substrate 409 placed on a substrate electrode 408. In this case, as shown in FIG. 24, by also supplying high-frequency power to the substrate electrode 408 by a substrate-electrode-use-high-frequency power supply 410, ion energy that reaches the substrate 409 can be controlled. In addition, the counter electrode 407 is insulated from the vacuum chamber 401 by an insulating ring 411. The matching box 405 comprises a high-frequency input terminal 412, a first variable capacitor 413, a high-frequency output terminal 414, a second variable capacitor 415, a first motor 416, a second motor 417, and a motor control circuit 418.
However, there has been an issue that the conventional method shown in FIG. 24 has difficulty in obtaining uniform plasma generation.
FIG. 25 shows results of measuring ion saturation current density at a position just 20 mm above the substrate 409 in the plasma processing apparatus of FIG. 24. Conditions for plasma generation are gas type of Cl2 and gas flow rate of 100 sccm, a pressure of 2 Pa and a high-frequency power of 1 kW. Also, as shown in FIG. 24, the second variable capacitor 415 is disposed on one side of the measuring position in FIG. 25. It can be understood from FIG. 25 that plasma density is higher on one side of the measuring position, i.e., just below the second variable capacitor 415.
Such nonuniformity of plasma is a phenomenon that could not be seen with the frequency of the high-frequency power of 50 MHz or less. Whereas the 50 MHz or higher high-frequency power needs to be used in order to lower the electron temperature of plasma, there develops, in this frequency band, a potential distribution in the counter electrode 407. It can be deduced that this potential distribution, affected by the placement of the second variable capacitor 415 within the matching box 405, acts to strengthen the electric fields just below the second variable capacitor 415, resulting in nonuniformity of plasma generation.
Such a phenomenon could be seen with such an arrangement as shown in FIG. 26 in which a spiral antenna 420 is used instead of the counter electrode 407. In the prior art example shown in FIG. 26, a dielectric window 421 is used.
In view of these issues of the prior art, an object of the present invention is to provide a plasma processing method and apparatus, as well as a matching box for a plasma processing apparatus, capable of generating uniform plasma.
In order to achieve the above object, the present invention has the following constitutions.
In accomplishing these and other aspects, according to a 1st aspect of the present invention, there is provided a plasma processing method for generating plasma within a vacuum chamber and processing a substrate placed on a substrate electrode within the vacuum chamber. The method comprises generating the plasma by supplying a high-frequency power having a frequency of 50 MHz to 3 GHz to a counter electrode provided opposite to the substrate while interior of the vacuum chamber is controlled to a specified pressure by introducing gas into the vacuum chamber and, simultaneously therewith, evacuating the interior of the vacuum chamber. The substrate is processed using the generated plasma while plasma distribution of the plasma on the substrate is controlled by an annular, groove-like plasma trap provided opposite to the substrate.
According to a 2nd aspect of the present invention, there is provided a plasma processing method for generating plasma within a vacuum chamber and processing a substrate placed on a substrate electrode within the vacuum chamber. The method comprises generating the plasma by radiating electromagnetic waves into the vacuum chamber via a dielectric window provided opposite to the substrate by supplying a high-frequency power having a frequency of 50 MHz to 3 GHz to an antenna while the interior of the vacuum chamber is controlled at a specified pressure by introducing gas into the vacuum chamber and, simultaneously therewith, evacuating the interior of the vacuum chamber. The substrate is processed using the generated plasma while plasma distribution of the plasma on the substrate is controlled by an annular, groove-like plasma trap provided opposite to the substrate.
According to a 3rd aspect of the present invention, there is provided a plasma processing method according to the 1st aspect, wherein the substrate is processed while a portion surrounded by the plasma trap out of a surface forming an inner wall surface of the vacuum chamber and opposing the substrate has an area 0.5 to 2.5 times that of the substrate.
According to a 4th aspect of the present invention, there is provided a plasma processing method according to the 1st aspect, wherein the substrate is processed while the plasma trap has a groove width of 3 mm to 50 mm.
According to a 5th aspect of the present invention, there is provided a plasma processing method according to the 1st aspect, wherein the substrate is processed while the plasma has a groove depth of not less than 5 mm.
According to a 6th aspect of the present invention, there is provided a plasma processing method according to the 1st aspect, wherein the substrate is processed while the plasma trap is provided in the counter electrode.
According to a 7th aspect of the present invention, there is provided a plasma processing method according to the 1st aspect, wherein the plasma is generated while the plasma trap is provided outside an insulating ring for insulating the vacuum chamber and the counter electrode from each other.
According to an 8th aspect of the present invention, there is provided a plasma processing method according to the 1st aspect, wherein the plasma is generated while the plasma trap is provided between the counter electrode and an insulating ring for insulating the vacuum chamber and the counter electrode from each other.
According to a 9th aspect of the present invention, there is provided a plasma processing method according to the 1st aspect, wherein the plasma is generated while the plasma trap is provided between the vacuum chamber and an insulating ring for insulating the vacuum chamber and the counter electrode from each other.
According to a 10th of the present invention, there is provided a plasma processing method according to the 2nd aspect, wherein the plasma is generated while the plasma trap is provided in the dielectric window.
According to an 11th aspect of the present invention, there is provided a plasma processing method according to the 2nd aspect, wherein the plasma is generated while the plasma trap is provided outside the dielectric window.
According to a 12th aspect of the present invention, there is provided a plasma processing method according to the 2nd aspect, wherein the plasma is generated while the plasma trap is provided between the vacuum chamber and the dielectric window.
According to a 13th aspect of the present invention, there is provided a plasma processing method according to the 1st aspect, wherein the plasma is generated while DC magnetic fields are absent within the vacuum chamber.
According to a 14th aspect of the present invention, there is provided a plasma processing apparatus comprising a vacuum chamber; a gas supply unit for supplying gas into the vacuum chamber; an evacuating device for evacuating the interior of the vacuum chamber; a substrate electrode for placing thereon a substrate within the vacuum chamber; a counter electrode provided opposite to the substrate electrode; high-frequency power supply capable of supplying a high-frequency power having a frequency of 50 MHz to 3 GHz to the counter electrode; and an annular, groove-like plasma trap provided opposite to the substrate.
According to a 15th aspect of the present invention, there is provided a plasma processing apparatus comprising: a vacuum chamber; a gas supply unit for supplying gas into the vacuum chamber; an evacuating device for evacuating the interior of the vacuum chamber; a substrate electrode for placing thereon a substrate within the vacuum chamber; a dielectric window provided opposite to the substrate electrode; an antenna for radiating electromagnetic waves into the vacuum chamber via the dielectric window; a high-frequency power supply capable of supplying a high-frequency power having a frequency of 50 MHz to 3 GHz to the antenna; and an annular, groove-like plasma trap provided opposite to the substrate.
According to a 16th aspect of the present invention, there is provided a plasma processing apparatus according to the 14th aspect, wherein a portion surrounded by the plasma trap out of a surface forming an inner wall surface of the vacuum chamber and opposing the substrate has an area 0.5 to 2.5 times that of the substrate.
According to a 17th aspect of the present invention, there is provided a plasma processing apparatus according to the 14th aspect, wherein the plasma trap has a groove width of 3 mm to 50 mm.
According to a 18th aspect of the present invention, there is provided a plasma processing apparatus according to the 14th or 15th aspect, wherein the plasma trap has a groove depth of not less than 5 mm.
According to a 19th aspect of the present invention, there is provided a plasma processing apparatus according to the 14th aspect, wherein the plasma trap is provided in the counter electrode.
According to a 20th aspect of the present invention, there is provided a plasma processing apparatus according to the 14th aspect, wherein the plasma trap is provided in an insulating ring for insulating the vacuum chamber and the counter electrode from each other.
According to a 21st aspect of the present invention, there is provided a plasma processing apparatus according to the 14th aspect, wherein the plasma trap is provided outside an insulating ring for insulating the vacuum chamber and the counter electrode from each other.
According to a 22nd aspect of the present invention, there is provided a plasma processing apparatus according to the 14th aspect, wherein the plasma trap is provided between the counter electrode and an insulating ring for insulating the vacuum chamber and the counter electrode from each other.
According to a 23rd aspect of the present invention, there is provided a plasma processing apparatus according to the 14th aspect, wherein the plasma trap is provided between the vacuum chamber and an insulating ring for insulating the vacuum chamber and the counter electrode from each other.
According to a 24th aspect of the present invention, there is provided a plasma processing apparatus according to the 15th aspect, wherein the plasma trap is provided in the dielectric window.
According to a 25th aspect of the present invention, there is provided a plasma processing apparatus according to the 15th aspect, wherein the plasma trap is provided outside the dielectric window.
According to a 26th aspect of the present invention, there is provided a plasma processing apparatus according to the 15th aspect, wherein the plasma trap is provided between the vacuum chamber and the dielectric window.
According to a 27th aspect of the present invention, there is provided a plasma processing apparatus according to the 14th aspect, wherein no coil or permanent magnet for applying DC magnetic fields is provided within the vacuum chamber.
According to a 28th aspect of the present invention, there is provided a plasma processing apparatus according to the 1st aspect, further comprising a matching box for use in the plasma processing apparatus and for taking impedance matching in supplying high-frequency power to a load. The matching box comprises a high-frequency input terminal; a first reactive element having one end connected to the high-frequency input terminal and the other end connected to a matching box casing; a high-frequency output terminal; and a second reactive element having one end connected to the high-frequency input terminal and the other end connected to the high-frequency output terminal. The second reactive element and the high-frequency output terminal are so arranged that the second reactive element is located on a straight line passing through a center axis of the high-frequency output terminal.
According to a 29th aspect of the present invention, there is provided a plasma processing apparatus according to the 28th aspect, wherein the first reactive element and the second reactive element are capacitors, respectively.
According to a 30th aspect of the present invention, there is provided a matching box for use in a plasma processing apparatus and for taking impedance matching in supplying high-frequency power to a load. The matching box comprises a high-frequency input terminal; a first reactive element having one end connected to the high-frequency input terminal and the other end connected to a matching box casing; a high-frequency output terminal; and a second reactive element having one end connected to the high-frequency input terminal and the other end connected to the high-frequency output terminal. The second reactive element and the high-frequency output terminal are so arranged that the second reactive element is located on a straight line passing through a center axis of the high-frequency output terminal.
According to a 31st aspect of the present invention, there is provided a matching box for a plasma processing apparatus according to the 30th aspect, wherein the second reactive element and the high-frequency output terminal are arranged so that a straight line passing through a center axis of the second reactive element and a straight line passing through the center axis of the high-frequency output terminal are generally coincident with each other.
According to a 32nd aspect of the present invention, there is provided a matching box for a plasma processing apparatus according to the 30th aspect, wherein the first reactive element and the second reactive element are capacitors, respectively.
According to a 33rd aspect of the present invention, there is provided a matching box for a plasma processing apparatus according to the 30th aspect, wherein the first reactive element and the second reactive element are arranged so that a straight line passing through a center axis of the second reactive element and a straight line passing through a center axis of the first reactive element are generally coincident with each other.
According to a 34th aspect of the present invention, there is provided a matching box for a plasma processing apparatus according to the 30th aspect, wherein the high-frequency output terminal is the other end itself of the second reactive element.
According to a 35th aspect of the present invention, there is provided a plasma processing method for generating plasma within a vacuum chamber and processing a substrate placed on a substrate electrode within the vacuum chamber. The method comprises arranging a straight line passing through a center axis of the high-frequency coupling device, a straight line passing through a center axis of the counter electrode or antenna, and a straight line passing through a center axis of the substrate so as to be generally coincident together.
The interior of the vacuum chamber maintained at a specified pressure by introducing a gas into the vacuum chamber and, simultaneously therewith, exhausting the interior of the vacuum chamber. The plasma is generated by applying a high-frequency power having a frequency of 50 MHz to 300 MHz to a counter electrode or antenna provided opposite to the substrate via the matching box as defined in the 30th aspect and a high-frequency coupling device provided to connect a high-frequency output terminal of the matching box and the counter electrode or antenna to each other. The substrate is then processed by using generated plasma.
According to a 36th aspect of the present invention, there is provided a plasma processing method according to the 35th aspect, in which the following additional steps are accomplished before maintaining the interior of the vacuum chamber at the specified pressure. A straight line passing through a center axis of the high-frequency output terminal and a straight line passing through the center axis of the high-frequency coupling device as arranged so as to be generally coincident with each other. The plasma is generated with the straight line passing through the center axis of the high-frequency output terminal and the straight line passing through the center axis of the high-frequency coupling device being generally coincident with each other.
According to a 37th aspect of the present invention, there is provided a plasma processing method according to the 35th aspect, in which the following additional steps are accomplishing before maintaining the interior of the vacuum chamber at the specified pressure. The first reactive element and the second reactive element are arranged so that a straight line passing through a center axis of the second reactive element and a straight line passing through a center axis of the first reactive element are generally coincident with each other. The plasma is generated with the straight line passing through the center axis of the second reactive element and the straight line passing through the center axis of the first reactive element being generally coincident with each other.
According to a 38th aspect of the present invention, there is provided a plasma processing method according to the 35th aspect, in which before maintaining the interior of the vacuum chamber at the specified pressure, the high-frequency output terminal is arranged so as to be the other end itself of the second reactive element, and the plasma is generated with the high-frequency output terminal being the other end itself of the second reactive element.
According to a 39th aspect of the present invention, there is provided a plasma processing method according to the 35th aspect, in which before controlling the interior of the vacuum chamber at the specified pressure, a substantial distance is arranged from the other end of the second reactive element to the counter electrode or antenna so as not to be more than {fraction (1/10)} of the wavelength of the high-frequency power. The plasma is generated with the substantial distance from the other end of the second reactive element to the counter electrode or antenna being not more than {fraction (1/10)} of the wavelength of the high-frequency power.
According to a 40th aspect of the present invention, there is provided a plasma processing method for generating plasma within a vacuum chamber and processing a substrate placed on a substrate electrode within the vacuum chamber. The method comprises arranging a straight line passing through a center axis of the high-frequency coupling device, a straight line passing through a center axis of the counter electrode or antenna, and a straight line passing through a center axis of the substrate so as to be generally coincident together. The interior of the vacuum chamber is maintained at a specified pressure by introducing a gas into the vacuum chamber and, simultaneously therewith, the interior of the vacuum chamber is exhausted. The plasma is generated by applying a high-frequency power having a frequency of 50 MHz to 300 MHz to a counter electrode or antenna provided opposite to the substrate via the matching box as defined in the 30th aspect and a high-frequency coupling device provided to connect a high-frequency output terminal of the matching box and the counter electrode or antenna to each other, and the substrate is processed by using the generated plasma.
According to a 41st aspect of the present invention, there is provided a plasma processing method according to the 40th aspect, in which before controlling the interior of the vacuum chamber to the specified pressure, a straight line passing through a center axis of the high-frequency output terminal and a straight line passing through the center axis of the high-frequency coupling device are arranged so as to be generally coincident with each other. The plasma is generated with the straight line passing through the center axis of the high-frequency output terminal and the straight line passing through the center axis of the high-frequency coupling device being generally coincident with each other.
According to a 42nd aspect of the present invention, there is provided a plasma processing method according to the 40th aspect, in which before controlling the interior of the vacuum chamber at the specified pressure, the first variable capacitor and the second variable capacitor are arranged that a straight line passing through a center axis of the second variable capacitor and a straight line passing through a center axis of the first variable capacitor are generally coincident with each other. The plasma is generated with the straight line passing through the center axis of the second variable capacitor and the straight line passing through the center axis of the first variable capacitor being generally coincident with each other.
According to a 43rd aspect of the present invention, there is provided a plasma processing method according to the 40th aspect, in which before controlling the interior of the vacuum chamber to the specified pressure, the high-frequency output terminal is arranged so as to be the other end itself of the second reactive element. The plasma is generated with the high-frequency output terminal being the other end itself of the second variable capacitor.
According to a 44th aspect of the present invention, there is provided a plasma processing method according to the 40th aspect, in which before controlling the interior of the vacuum chamber to the specified pressure, a substantial distance is arranged from the other end of the second variable capacitor to the counter electrode or antenna so as to be not more than {fraction (1/10)} of wavelength of the high-frequency power. The plasma is generated with the substantial distance from the other end of the second variable capacitor to the counter electrode or antenna to be not more than {fraction (1/10)} of wavelength of the high-frequency power.
According to a 45th aspect of the present invention, there is provided a plasma processing apparatus comprising: a vacuum chamber; a gas supply unit for supplying gas into the vacuum chamber; an evacuating device for evacuating the interior of the vacuum chamber; a substrate electrode for placing thereon a substrate within the vacuum chamber; a counter electrode or an antenna provided opposite to the substrate electrode; a high-frequency power supply capable of supplying a high-frequency power having a frequency of 50 MHz to 300 MHz to the counter electrode or antenna; the matching box as defined in the 30th aspect; and a high-frequency coupling device for connecting the high-frequency output terminal of the matching box and the counter electrode or antenna to each other. A straight line passing through a center axis of the high-frequency coupling device, a straight line passing through a center axis of the counter electrode or antenna, and a straight line passing through a center axis of the substrate are arranged so as to be generally coincident together.
According to a 46th aspect of the present invention, there is provided a plasma processing apparatus according to the 45th aspect, wherein a straight line passing through a center axis of the high-frequency output terminal and a straight line passing through the center axis of the high-frequency coupling device are arranged so as to be generally coincident with each other.
According to a 47th aspect of the present invention, there is provided a plasma processing apparatus according to the 45th aspect, wherein the first reactive element and the second reactive element are arranged so that a straight line passing through a center axis of the second reactive element and a straight line passing through a center axis of the first reactive element are generally coincident with each other.
According to a 48th aspect of the present invention, there is provided a plasma processing apparatus according to the 45th aspect, wherein the high-frequency output terminal is the other end itself of the second reactive element.
According to a 49th aspect of the present invention, there is provided a plasma processing apparatus according to the 45th aspect, wherein substantial distance from the other end of the second reactive element to the counter electrode or antenna is not more than {fraction (1/10)} of wavelength of the high-frequency power.
According to a 50th aspect of the present invention, there is provided a plasma processing apparatus comprising a vacuum chamber; a gas supply unit for supplying gas into the vacuum chamber; an evacuating device for evacuating the interior of the vacuum chamber; a substrate electrode for placing thereon a substrate within the vacuum chamber; a counter electrode or an antenna provided opposite to the substrate electrode; a high-frequency power supply capable of supplying a high-frequency power having a frequency of 50 MHz to 300 MHz to the counter electrode or antenna; the matching box as defined in the 30th aspect; and a high-frequency coupling device for connecting the high-frequency output terminal of the matching box and the counter electrode or antenna to each other. A straight line passing through a center axis of the high-frequency coupling device, a straight line passing through a center axis of the counter electrode or antenna, and a straight line passing through a center axis of the substrate are arranged so as to be generally coincident together.
According to a 51st aspect of the present invention, there is provided a plasma processing apparatus according to the 50th aspect, wherein the plasma is generated while the straight line passing through the center axis of the high-frequency output terminal and the straight line passing through the center axis of the high-frequency coupling device are arranged so as to be generally coincident with each other.
According to a 52nd aspect of the present invention, there is provided a plasma processing apparatus according to the 50th aspect, wherein a first variable capacitor and a second variable capacitor are arranged so that a straight line passing through a center axis of the second variable capacitor and a straight line passing through a center axis of the first variable capacitor are generally coincident with each other.
According to a 53rd aspect of the present invention, there is provided a plasma processing apparatus according to the 50th aspect, wherein the high-frequency output terminal is the other end itself of the second variable capacitor.
According to a 54th aspect of the present invention, there is provided a plasma processing apparatus according to the 50th aspect, wherein a substantial distance from the other end of the second variable capacitor to the counter electrode or antenna is not more than {fraction (1/10)} of the wavelength of the high-frequency power.